Trend Of Accelerated Testing Creates Opportunities For Manufacturers To Bring Products To Market Sooner

As the saying goes, "First to market, first to profit." In the race to debut new products, every marketing manager knows that beating the competition to the punch can provide a head start that can last throughout the product's life cycle. Yet, to securely maintain that edge, the product must consistently deliver on its promise, which means that quality can never be compromised.

To fulfill both requirements of delivering reliable products, on-time, accelerated testing techniques are quickly being adopted to the point that manufacturers who don't employ them stand to fall out of the race. For this reason, both HALT (Highly Accelerated Life Testing) and HASS (Highly Accelerated Stress Screenings) are gaining acceptance as the new standards for product development and process control.

A proactive testing mentality
Every manufacturer whose product contains a microprocessor, circuit card or electromechanical assembly can benefit from accelerated test methods that enable companies to develop products quickly, free of design flaws and within budget.

Such a proactive approach stands in contrast to testing procedures used in the past that typically consumed weeks or months. Additionally, because many conventional test procedures call out minimum specifications and nothing more, traditional DVT tests only within specification, missing design defects detectable by over-stress techniques. This results in product failures in the field, costly product recalls, ongoing warranty expenses and time-consuming support programs.

HALT and HASS techniques shortcut and avoid these problems by quickly exposing any weak links in a product so they can be fixed before they become expensive field issues. In effect, HALT and HASS ferret out any weak links in design and/or production processes in order to make great products even better.

HALT and HASS defined
HALT Testing is a proven method to find design defects. Without discovery, design defects often appear in end-use applications, causing product failures after release. But HALT increases product reliability by pushing a product to its operating limits and beyond. With HALT, a product is subjected to the outer margins of temperature, rapid thermal cycling, and vibration testing to rapidly uncover any design weaknesses.

"Most traditional testing checks the product up to the spec', but HALT goes way beyond that," says Mike Silverman, Managing Partner of Ops Ala Carte, LLC, a professional consulting firm based in Saratoga, California that focuses on reliability engineering services. "For example, let's say a cellphone manufacturer says their product will work up to 50° C. Well, HALT will actually take that phone up to 70, 80, or 90° C, in order to find any weaknesses before the product goes out the door. That, in itself, is acceleration, because we are accelerating any possible failure mechanisms and bringing them back into the laboratory so the customer doesn't see them."

After HALT has revealed any product weaknesses, proper Root Cause of Failure analysis facilitates the corrective action necessary to improve the design. As a result, HALT reduces R&D costs, shortens the time to market, and increases product quality and reliability. Once an approved design goes into production, HASS testing comes into play to ensure that any weak leaks in the manufacturing processes do not undermine the already-proven design. In essence, the goal of a HASS is to detect failure modes that can be introduced in the production of the product.

"In HASS, the product is subjected to much the same tests performed in HALT, but the goals of the test are different," says Silverman. "HASS is a manufacturing screening process that focuses on process issues, such as assembly errors, in order to remove any possible infant mortality in the product -- mostly in the area of hardware -- before the product is released."

HASS proves effective in screening-out failures that may have gone undetected during traditional burn-in testing processes. It also goes beyond normal testing to verify the integrity of mechanical interconnects and component tolerance compatibility, and can even uncover "timing" errors that only occur under high stress. A product that passes HASS testing assures manufacturing-process quality and workmanship integrity. This results in increased out-of-box quality and field reliability, which yields decreased field service and warranty costs.

Maximizing the benefits of HALT and HASS
Ultimately, the benefits of increased product reliability help push up the bottom line of any manufacturer. In the long run, the outcome is higher customer satisfaction and confidence, increased company image and reputation, and increased market share.

Yet, realizing the full potential of HALT and HASS rests on employing the correct testing equipment and procedures.

"Certainly, combining vibration testing and thermal cycling in the same step speeds the process, but I would say that the main thing that accelerates products to market is that failures can be created much more quickly by using HALT and HASS than with standard reliability improvement techniques," says Ed Kyser, Ph.D., consultant and author of several articles on accelerated stress testing and holder of seven U.S. patents. Dr. Kyser's company, Reliability Economics-based in Los Altos, California - provides assessment and economic analysis of all aspects of reliability and quality improvements programs. "The reason: we're stressing the product/component beyond its design limits. To me, that is the genius behind this kind of approach to finding faults and fixing them."

Because accelerated testing covers an extremely broad range of products, applying the "genius" requires expertise in determining which equipment and testing procedures are best for a particular application. For instance, HASS is not intended to be a rigid process that has an endpoint, but rather a dynamic process that may need modification or adjustment over the life of the product. Since HASS levels are more aggressive than conventional screening tools, a proof-of-screen (POS) procedure is vital to determine that the HASS stresses are capable of revealing production defects.

Companies such as Denver, Colorado-based QualMark Corporation¾a leader in designing, marketing, and manufacturing accelerated life-testing systems - add value to the sale of accelerated testing equipment by counseling manufacturers on how to successfully set up these testing procedures.

"I know how to work through the numbers and make that kind of judgment, and have lent my expertise to QualMark so they can help customers determine how to make a testing chamber pay off," adds Kyser. "In this manner, a company like QualMark offers not just a chamber, but the service and expertise to go with it."

QualMark has installed more than 600 of its proprietary testing systems in 30 countries for many major corporations and one of the largest computer companies in the world.

To further secure its position as a leader in its field, QualMark recently acquired Massachusetts-based Ling Electronics - a manufacturer of the most complete line of electrodynamic shakers and amplifiers, ranging from 100 force pounds to 40,000 force pounds. This acquisition now gives QualMark a leading position in both the HALT/HASS marketplace as well as the traditional electrodynamic shaker marketplace.

QualMark's patented OVS (OmniAxial Vibration System) tables used in their HALT and HASS chambers excite every part of a product, down to the component level, at its resonant frequency. This requires vibration in all three axes as well as the rotation around those axes, simultaneously, across a wide frequency range. At the same time, and within the same chamber, thermal tests are undertaken. The chamber's patented Typhoon air-handling technology drives products from ambient to the appropriate stress temperature quickly using less electricity and liquid nitrogen, providing the lowest total cost of chamber ownership for everyday operation.

"If you looked at a pie-chart and it showed all possible defects, you'd have a certain percentage showing up at extreme high and low temperatures, during thermal cycling, under vibration in all axes, and during combined vibration and thermal cycling," notes Charlie Bates, vice president of program development for QualMark. "To cover all the bases you have to test both vibe' and temp simultaneously, because studies have shown that you can otherwise miss 25-30% of the defects."

In addition, thorough HALT and HASS testing requires broad frequency excitation, far beyond what a product might see in the end use environment, to ensure that weak links are quickly exposed.

"Our new xLF vibration system is unique in shifting the energy in the frequency domain down to the zero to 5,000 Hz range. With 50% of the energy below 2,000 Hz and 50% above, we simulate the resident frequencies in various types of electronic hardware, including printed circuit boards," continues Bates. "This quickly brings out potential real-world problems such as weak solder joints and incomplete surface mount connections."

Experienced consulting services¾tailoring testing procedures to meet specific needs - in conjunction with the proper equipment, help enhances the effectiveness of accelerated testing methods. As an example, QualMark authorized test centers have conducted over 4,000 HALT and HASS tests since 1991, employing services such as customer directed testing, production screening, production HASA (Highly Accelerated Stress Audits), and on-site testing.

SOURCE: Power PR